Sahih al-Bukhari 1790
In-book no 1790حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ يُونُسَ، حَدَّثَنَا حَاتِمُ بْنُ إِسْمَاعِيلَ، عَنْ مُحَمَّدِ بْنِ يُوسُفَ، عَنِ السَّائِبِ بْنِ يَزِيدَ، قَالَ حُجَّ بِي مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم وَأَنَا ابْنُ سَبْعِ سِنِينَ.
Narrated As-Sa'ib bin Yazid: (While in the company of my parents) I was made to perform Hajj with Allah's Messenger (ﷺ) and I was a seven-year-old boy then. (Fath-ul-Bari, p.443, Vol.4)